Debuggers or debugging computer programs are used by computer programmers to methodically work their way through or into specific regions of a particular program that has been written. The programmers are then able to make alterations and corrections so that the program will operate and function properly without either giving erroneous results or becoming locked up such that it cannot continue.
Debugging programs, commonly referred to as debuggers, can, in effect, override normal operation and operational controls of a program so that the operator may look into or get into a program or the storage locations in which the program is stored. This allows the programmer to control the step-by-step operation of the program being debugged and also allows the programmer to inspect the contents of any particular memory location in physical memory to ensure that the proper values are stored in that location as well as giving the programmer direct access to that location to make alterations or corrections. Using a debugger, a programmer may get into the inner workings of an operating system, an application program or device driver programs. Device driver programs which interface between the application program and an input/output device, such as a printer, disk file or other device which provides signals to the program and receives signals and commands from the program controlled processor to perform some function.
There exists more than one kind of debugger program. Once such type is a kernel level debugger. This type of debugger is embedded into the operating system with which it functions and allows the programmer access to the operating system and higher level programs, such as application programs or device driver programs, that are running with the operating system.
A second type of program for debugging is a separate stand-alone debugging program or debugger such as the present invention and allows the debugging of computer programs without having to load the kernel level spin of the operating system. This is desirable because bugs found in programming on what may be referred to as the retail level of the operating system (the level ultimately delivered to the customer) may be permuted or be masked when running on the kernel level spin of the operating system. This may be due to the fact that when the debugger portion of the kernel level spin is added, there are sufficient changes made in the program environment to cause the base program no longer to reflect its operation as it exists in the retail level.
Where the debugger program is not embedded in the operating system, any bugs in the program being debugged or any problems with that program are more readily identifiable and correctable because it is running in its natural environment, the retail spin or level of the operating system.
Kernel level debuggers integrated into the operating system program have built in hooks or interrupt intercepts to allow the computer programmer to monitor events as a program operates.